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7#include <linux/kernel.h>
8#include <linux/export.h>
9#include <linux/ftrace.h>
10#include <linux/kprobes.h>
11#include <linux/sched.h>
12#include <linux/sched/debug.h>
13#include <linux/sched/task_stack.h>
14#include <linux/stacktrace.h>
15
16#include <asm/irq.h>
17#include <asm/pointer_auth.h>
18#include <asm/stack_pointer.h>
19#include <asm/stacktrace.h>
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35
36void start_backtrace(struct stackframe *frame, unsigned long fp,
37 unsigned long pc)
38{
39 frame->fp = fp;
40 frame->pc = pc;
41#ifdef CONFIG_FUNCTION_GRAPH_TRACER
42 frame->graph = 0;
43#endif
44
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52
53
54 bitmap_zero(frame->stacks_done, __NR_STACK_TYPES);
55 frame->prev_fp = 0;
56 frame->prev_type = STACK_TYPE_UNKNOWN;
57}
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64
65
66int notrace unwind_frame(struct task_struct *tsk, struct stackframe *frame)
67{
68 unsigned long fp = frame->fp;
69 struct stack_info info;
70
71 if (!tsk)
72 tsk = current;
73
74
75 if (fp == (unsigned long)task_pt_regs(tsk)->stackframe)
76 return -ENOENT;
77
78 if (fp & 0x7)
79 return -EINVAL;
80
81 if (!on_accessible_stack(tsk, fp, 16, &info))
82 return -EINVAL;
83
84 if (test_bit(info.type, frame->stacks_done))
85 return -EINVAL;
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99
100 if (info.type == frame->prev_type) {
101 if (fp <= frame->prev_fp)
102 return -EINVAL;
103 } else {
104 set_bit(frame->prev_type, frame->stacks_done);
105 }
106
107
108
109
110
111 frame->fp = READ_ONCE_NOCHECK(*(unsigned long *)(fp));
112 frame->pc = READ_ONCE_NOCHECK(*(unsigned long *)(fp + 8));
113 frame->prev_fp = fp;
114 frame->prev_type = info.type;
115
116#ifdef CONFIG_FUNCTION_GRAPH_TRACER
117 if (tsk->ret_stack &&
118 (ptrauth_strip_insn_pac(frame->pc) == (unsigned long)return_to_handler)) {
119 struct ftrace_ret_stack *ret_stack;
120
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125
126 ret_stack = ftrace_graph_get_ret_stack(tsk, frame->graph++);
127 if (WARN_ON_ONCE(!ret_stack))
128 return -EINVAL;
129 frame->pc = ret_stack->ret;
130 }
131#endif
132
133 frame->pc = ptrauth_strip_insn_pac(frame->pc);
134
135 return 0;
136}
137NOKPROBE_SYMBOL(unwind_frame);
138
139void notrace walk_stackframe(struct task_struct *tsk, struct stackframe *frame,
140 bool (*fn)(void *, unsigned long), void *data)
141{
142 while (1) {
143 int ret;
144
145 if (!fn(data, frame->pc))
146 break;
147 ret = unwind_frame(tsk, frame);
148 if (ret < 0)
149 break;
150 }
151}
152NOKPROBE_SYMBOL(walk_stackframe);
153
154static void dump_backtrace_entry(unsigned long where, const char *loglvl)
155{
156 printk("%s %pSb\n", loglvl, (void *)where);
157}
158
159void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk,
160 const char *loglvl)
161{
162 struct stackframe frame;
163 int skip = 0;
164
165 pr_debug("%s(regs = %p tsk = %p)\n", __func__, regs, tsk);
166
167 if (regs) {
168 if (user_mode(regs))
169 return;
170 skip = 1;
171 }
172
173 if (!tsk)
174 tsk = current;
175
176 if (!try_get_task_stack(tsk))
177 return;
178
179 if (tsk == current) {
180 start_backtrace(&frame,
181 (unsigned long)__builtin_frame_address(0),
182 (unsigned long)dump_backtrace);
183 } else {
184
185
186
187 start_backtrace(&frame,
188 thread_saved_fp(tsk),
189 thread_saved_pc(tsk));
190 }
191
192 printk("%sCall trace:\n", loglvl);
193 do {
194
195 if (!skip) {
196 dump_backtrace_entry(frame.pc, loglvl);
197 } else if (frame.fp == regs->regs[29]) {
198 skip = 0;
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206 dump_backtrace_entry(regs->pc, loglvl);
207 }
208 } while (!unwind_frame(tsk, &frame));
209
210 put_task_stack(tsk);
211}
212
213void show_stack(struct task_struct *tsk, unsigned long *sp, const char *loglvl)
214{
215 dump_backtrace(NULL, tsk, loglvl);
216 barrier();
217}
218
219#ifdef CONFIG_STACKTRACE
220
221noinline notrace void arch_stack_walk(stack_trace_consume_fn consume_entry,
222 void *cookie, struct task_struct *task,
223 struct pt_regs *regs)
224{
225 struct stackframe frame;
226
227 if (regs)
228 start_backtrace(&frame, regs->regs[29], regs->pc);
229 else if (task == current)
230 start_backtrace(&frame,
231 (unsigned long)__builtin_frame_address(1),
232 (unsigned long)__builtin_return_address(0));
233 else
234 start_backtrace(&frame, thread_saved_fp(task),
235 thread_saved_pc(task));
236
237 walk_stackframe(task, &frame, consume_entry, cookie);
238}
239
240#endif
241